Treatment of IgA nephropathy

IgA nephropathy (IgAN) is an important cause of progressive kidney disease with 25-30% of patients developing end-stage renal disease within 20 years of diagnosis. There is still no treatment to modify mesangial IgA deposition and available treatments are those extrapolated from the management of other patterns of chronic glomerulonephritis. There remains no consensus on the use of immunosuppressive agents for treatment of progressive IgAN and this is compounded by the relative lack in IgAN of randomized controlled trials relevant to current clinical practice. Patients with recurrent macroscopic hematuria or isolated microscopic hematuria and proteinuria <1 g/24 h require no specific treatment. Those with nephrotic syndrome and minimal change on renal biopsy should be managed as for minimal change nephropathy. There is no evidence to support the use of corticosteroids for nephrotic IgAN outside this group of patients. Patients presenting with acute renal failure require evaluation to distinguish acute tubular necrosis, which requires supportive therapy only, from crescentic IgAN, for which treatment with cyclophosphamide and corticosteroids in a regimen similar to that for renal small vessel vasculitis is indicated in the absence of significant chronic histologic injury. Patients at greatest risk of progressive renal impairment are those with hypertension, proteinuria >1 g/24 h, and reduced glomerular filtration rate at diagnosis. All such patients should be treated to a blood pressure of 125/75 mm Hg with dual blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibition and angiotensin receptor blockade. At present, there is insufficient evidence for the additional use of immunosuppressive agents, antiplatelet agents, or anticoagulants.     

Proteinuria in IgA nephropathy

Clinicopathological data in 74 patients with IgA nephropathy were analyzed with special attention to level of proteinuria and its prognostic significance in this disease. Excretion rates exceeding 3 g per day (heavy), in the range of 1 to 2.9 g (moderate) and under 1 g per day (mild) each occurred in approximately equal proportions of patients. One-sixth of those with more than 1 g developed end-stage renal failure, while serum creatinine never exceeded 2 mg/dl in any with mild proteinuria. "Renal survival" (serum creatinine of 2 mg/dl or less) at five years after presentation was 100% in patients with persistently mild proteinuria, 87% in those whose protein excretion reached the moderate range, and 69% when heavy or nephrotic range proteinuria developed. Of significance, only rarely did mild proteinuria at presentation increase to higher levels. A correlation existed between level of protein excretion and severity of mesangial, segmental or global proliferation, glomerulosclerosis, podocyte effacement, interstitial infiltration, tubular atrophy and vascular sclerosis, even in patients with unimpaired renal function. Moderate or heavy proteinuria typically preceded the onset of hypertension and occurred prior to the development of renal insufficiency. Our results underscore magnitude of proteinuria as an early marker of glomerular damage in the prognosis of IgA nephropathy.     

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers for IgA nephropathy

The lengthy course of IgA nephropathy and the possibility of good outcomes without therapy suggest nontoxic therapies such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs.) Among patients with IgA nephropathy, both ACE inhibitors and ARBs reduce the transglomerular passage of large, but not small, molecules, reducing proteinuria. The antiproteinuric effects of ACE inhibitors and ARBs are probably equivalent. Dual ACE inhibitor-ARB therapy reduces proteinuria by 54% to 73% and is more effective than either agent alone. To determine whether ACE inhibitors or ARBs preserve renal function long-term, one must rely on trials studying nondiabetic, proteinuric renal diseases rather than on trials specific to IgA nephropathy. Among this group of patients, several randomized, controlled trials, including the AIPRI trial, the REIN trial, and a metaanalysis of 11 randomized, controlled trials, have established clearly that the ACE inhibitors preserve renal function. There is no reason to believe that this information is not applicable to IgA nephropathy. The COOPERATE trial, in which 50% of the subjects had IgA nephropathy, established that ACE inhibitors and ARBs preserve renal function equally, and that dual ACE inhibitor-ARB therapy preserves renal function more effectively than either therapy alone. These data suggest that most individuals with proteinuric renal diseases, including IgA nephropathy, should be treated with ACE inhibitors and ARBs, ideally in combination. Polymorphisms of the angiotensinogen gene, the ACE gene, and the angiotensin II type I receptor gene have, so far, failed to predict either susceptibility to or progression of IgA nephropathy. However, the D allele of the ID polymorphism, particularly the DD genotype, could predict a favorable response to renin-angiotensin blockade.     

Nephrotic-range proteinuria in a patient with a renal allograft treated with sorafenib for metastatic renal-cell carcinoma

A 51-year-old man with immunoglobulin A (IgA) nephropathy developed metastatic renal-cell carcinoma of his native right kidney, 3.5 years post kidney transplant. At that time renal function was stable with the presence of only mild proteinuria. Shortly after chemotherapy with sorafenib [anti-vascular endothelial growth factor (VEGF)] was initiated, progressive renal impairment, hypertension, and nephrotic-range proteinuria developed. Allograft biopsy showed extensive IgA nephropathy. After withdrawal of the anti-VEGF therapy, however, renal function and blood pressure improved, and proteinuria diminished. Based on the clinical course and histopathological findings we hypothesize that sorafenib may induce nephrotic-range proteinuria and renal impairment, possibly through anti-VEGF-mediated effects on the progression of IgA nephropathy.     

Angiotensin-converting enzyme insertion/deletion polymorphism and prognosis of IgA nephropathy

BACKGROUND/AIM: Well-known factors for a poor prognosis in IgA nephropathy (IgAN) are hypertension, proteinuria, and renal insufficiency at the time of diagnosis. Also hypertriglyceridemia and hyperuricemia seem to play a role in the progression of IgAN. Angiotensin-converting enzyme (ACE) gene I/D polymorphism has been associated with cardiovascular diseases and with progression of IgAN. We, therefore, investigated the contribution of ACE gene I/D polymorphism in the prognosis of IgAN and its association with the other risk factors affecting the prognosis. METHODS: A total of 168 patients with IgAN were followed up for 6-17 (median 11) years from renal biopsy with respect to progression of renal disease defined as elevation of serum creatinine above 125 microM (1.4 mg/dl) in men or 105 microM (1.2 mg/dl) in women and over 20% from the baseline level. In addition to serum creatinine, the urinary protein excretion was evaluated at the time of renal biopsy and at the assessment visit at the end of the follow-up period. RESULTS: During the follow-up period, 26 (15%) patients showed progression of renal disease. Patients with ACE genotype II had a more favorable course than those with genotypes ID or DD. Although there were no significant differences among the ACE genotypes with respect to proteinuria > or =1 g/24 h at the time of renal biopsy, proteinuria > or =1 g/24 h was more frequent in patients with genotypes ID or DD than in those with genotype II at the end of the follow-up period. No associations were found between hypertension, serum lipids or serum urate, and ACE genotypes. CONCLUSIONS: Our results show that patients with ACE genotype II have a more favorable prognosis than those with genotypes ID/DD. Secondly, proteinuria (> or =1 g/24 h) found in patients with genotype II at diagnosis may improve, while in patients with genotypes ID/DD it is a more constant feature.     

Iga nephropathy: presentation, clinical course, and prognosis in children and adults

Eighty-two patients, 56 male and 26 female, biopsied since 1972 had IgA nephropathy. At the time of kidney biopsy, 24 patients were children and 58 were adults. In both groups the clinical course was documented in sufficient detail to allow prediction of disease outcome. Twenty-six (45%) of the adult patients had chronic renal insufficiency either at first evaluation or subsequently. Fourteen eventually required chronic hemodialysis. Hypertension as the initial sign of disease was seen more frequently in patients with chronic renal insufficiency. Adult males were more likely to have chronic renal insufficiency. The life table method was used to predict age at initiation of dialysis and kidney survival from date of onset of clinically apparent disease. Thirty-five percent of the male patients were predicted to require dialysis by age 40. Kidney death was predicted at 10 years from onset for 33% of male and 22% of all patients biopsied as adults. While all patients with progressive disease had over 2.0 g/24 h urinary protein excretion at least once, many individuals with serum creatinine concentration below 1.5 mg/dL showed marked fluctuation in degree of proteinuria, often exceeding 2.0 g/24 h. Thus, in some cases, degree of proteinuria was not a reliable predictor of outcome.     

Crescentic, proliferative IgA nephropathy: clinical and histological response to methylprednisolone and intravenous cyclophosphamide.

BACKGROUND: IgA nephropathy is an immune-complex glomerulopathy that can result in capillary or extra-capillary proliferation. Previous attempts to correlate specific histological findings including cellular crescents or endocapillary proliferation, with clinical outcomes, have produced conflicting results. METHODS: We conducted a prospective open-labelled trial of 12 patients with crescentic, proliferative IgA nephropathy and clinically progressive disease and treated them with pulse steroids and intravenous cyclophosphamide. Therapy included pulse solumedrol at 15 mg/kg/day for 3 days, followed by monthly intravenous cyclophosphamide at 0.5 g/m(2) body surface area for 6 months. Clinically significant proteinuria (>1.0 g/24 h) was present in all patients, while nephrotic-range proteinuria (>3.0 g/24 h) was observed in eight of 12 patients. All patients were hypertensive (BP >140/90 mmHg). RESULTS: After 6 months of treatment, the mean serum creatinine was reduced from a maximum of 2.65+/-0.39 to 1.51+/-0.10 mg/dl (P<0.03), while proteinuria was reduced from 4.04 to 1.35 g/24 h (P<0.01). The mean slope of 1/serum creatinine increased from -0.0398+/-0.02 to 0.0076+/-0.01 after 6 months of therapy, but this trend did not reach statistical significance (P<0.08). A repeat kidney biopsy was performed in all treated patients. Endocapillary proliferation, cellular crescents and karyorrhexis were eliminated in all 12 patients after 6 months of therapy, while interstitial fibrosis and tubule dropout remained unchanged. To determine the long-term efficacy of the treatment, treated patients were compared to 12 historical controls matched for severity of IgA on initial biopsy. After 36 months, the rate of end-stage renal disease in the treated group was lower (1/12) than in the historical controls (5/12). CONCLUSIONS: We conclude that steroids and intravenous cyclophosphamide reduce proliferative lesions, reduce proteinuria and stabilize renal function in patients with crescentic IgA nephropathy.     

Polymorphism of renin-angiotensin system genes in progressive IgA nephropathy

Summary: Clinical studies revealed that angiotensin converting enzyme (ACE) inhibitor reduces proteinuria and attenuates progressive decline in renal function in IgA nephropathy. Recent studies by us and others have demonstrated that the homozygote of the D allele (DD) of the ACE insertion/deletion (I/D) polymorphism is a potential risk factor for poor prognosis in IgA nephropathy, and that this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function in patients with the nephropathy.     

少量蛋白尿IgA肾病临床研究现状

少量蛋白尿IgA肾病(24 h尿蛋白<1 g)的患者既往认为长期预后良好,且肾活检比例低,普遍未予积极有效的治疗。近年来陆续有研究表明,少量蛋白尿IgA肾病患者长期预后并不乐观,因此需提高对少量蛋白尿IgA肾病临床、病理、治疗及预后的认识及理解。本文将对少量蛋白尿IgA肾病临床表现、肾脏病理、治疗及预后4个方面予以综述。     

IgA nephropathy in children: significance of glomerular basement membrane deposition of IgA

Seventeen children with IgA nephropathy were grouped according to the absence (group I, n = 10) or presence (group II, n = 7) of glomerular basement membrane (GBM) deposition of IgA to determine whether GBM deposition of IgA correlated with laboratory or pathologic data at diagnosis or clinical status at follow-up. Children in group II had significantly (p less than 0.01) more proteinuria at diagnosis than children in group I. The percentage of glomeruli demonstrating crescent formation was significantly (p less than 0.05) higher in group II biopsies. Chronic changes of fibrous crescents, segmental sclerosis, global obsolescence, tubular atrophy, and interstitial fibrosis were also significantly (p less than 0.001) more common in group II biopsies. After a mean follow-up period of 2 years, all children in group II have persistent proteinuria of more than 1 g/24 h, and 3 of 5 have renal insufficiency (2 require dialysis). In contrast, 2 of 9 group I children have proteinuria exceeding 1 g/24 h, and only 1 has renal insufficiency. We conclude that, as compared to children with IgA localized to the mesangium, children with IgA nephropathy and GBM deposition of IgA have a higher urinary protein excretion at the time of diagnosis, more severe histologic alterations including a greater percentage of glomeruli demonstrating crescent formation, more chronic changes of segmental or global sclerosis, tubular atrophy, and interstitial fibrosis. Such children usually have persistent proteinuria and are more likely to develop progressive renal disease.     

Glomérulonéphrite à dépôts mésangiaux d’IgA

IgA nephropathy is the primitive glomerulonephritis the most frequently encountered worldwide. In about one case out of three, it is responsible for the progression from progressive renal failure to end-stage renal failure. The pathophysiological mechanisms of this disease which is mediated by immune complexes remain unclear. The presentation, clinical progression and optical microscope aspect of the renal biopsy may widely vary, making any histological classification very difficult. Most therapeutic studies include the patients only on clinical criteria of severity. The only consensual management is that of patients with a nephropathy and mild glomerular lesions and a nephritic syndrome, or with an extracapillar glomerulonephritis and a rapidly progressive renal failure; corticoids are indicated in former cases while corticoids must be combined with immunosuppressive agents in the latter ones. Corticotherapy may be considered in patients with a proteinuria higher than 1 g/day without renal failure. In any patient with primitive IgA nephropathy, the overall management used for chronic glomerulopathy must be initiated, including, in case of arterial hypertension or proteinuria, the renin-angiotensin system blockade.     

ACE inhibition reduces proteinuria in normotensive patients with IgA nephropathy: a multicentre, randomized, placebo-controlled study

A multicentre, randomized, placebo-controlled study was performedin 39 adult patients with biopsy-proven IgA nephropathy withthe aim of comparing the effects of the ACE inhibitor fosinopriland placebo on proteinuria. All patients had normal blood pressureand normal renal function. Proteinuria ranged from 1.0 to 2.5g/24 h. After a 3-month run-in period, fosinopril and placebowere randomly administered in two 4-month sequences separatedfrom crossover treatment by a 1-month interval. The mean valuesof creatinine clearance did not change during either the placeboor the treatment sequences. The mean values of mean arterialpressure (MAP) were significantly lower during the fosinoprilsequence (90.4 ±9.0 mmHg) than in basal conditions (92.8± 9.1 mmHg) (P=0.034). The mean basal values of proteinuriawere 1.74 ±0.84 g/24 h. They were unchanged during theplacebo sequence (1.79 ±1.20) and fell to 1.37 ±0.98g/24 h after 4 months of fosinopril treatment. Using a multivariatestatistical analysis, the treatment effect by time on proteinuriawas significantly evident only in the fosinopril sequence (Wilkstest, P=O.O33). Changes in protein excretion were not correlatedwith changes in MAP, baseline plasma renin activity, and urinarysodium excretion. This controlled study shows that fosinoprilcan significantly reduce proteinuria even in normotensive patientswith IgA nephropathy. Obviously, the results of treatment withACE inhibitors on long-term renal prognosis remain to be elucidated.     

Treatment of IgA nephropathy: an overview

Summary: The results of proposed approaches to the treatment of IgA nephropathy are discussed, stressing the difficulty of their correct evaluation due to the variable evolution of the disease. There is no convincing evidence that supports a beneficial effect for many of the therapeutical remedies with the following exceptions: (i) steroids are effective in the rare patients with selective proteinuria in the nephrotic range and very mild lesions by light microscopy (minimal change nephropathy with IgA mesangial deposits). the use of steroids is useful, in association with cyclophosphamide, even in patients with morphological features of intraglomerular capillaritis (segmental necrotizing lesions) and/or extracapillary proliferation in more than 25% of glomeruli (independently of the presence of diffuse circumferential crescents and a rapidly progressive course). A controlled trial that is underway will attempt to establish whether steroids can be effective in retarding deterioration of renal function in other subgroups of patients at risk of progression; (ii) fish-oil, administered orally (12 g/day for 2 years), is beneficial in patients at risk of progression (marked proteinuria, moderately impaired renal function, arterial hypertension and morphological features of active disease); and (iii) long-term administration of angiotensin converting enzyme (ACE)-inhibitors, even in the absence of arterial hypertension, seem to slow the progression and reduce the protein loss in the same group of patients at risk.     

Successful treatment of combination therapy using an angiotensin-converting enzyme inhibitor and an angiotensin II receptor blocker in a patient with IgA nephropathy

A 24-year-old Japanese woman with IgA nephropathy was admitted to our hospital due to the development of proteinuria and pretibial edema while on glucocorticoids and an angiotensin-converting-enzyme(ACE) inhibitor. She had been on both medications for more than 2 years. Urinary protein excretion was 2.53 g/day and renal function laboratory data were within the normal range. Plasma aldosterone concentration was high at 248 pg/ml, with normal plasma renin activity. The renal biopsy specimens showed prominent glomerular hypertrophy. Four weeks after the addition of valsartan, an angiotensin II receptor blocker(ARB), urinary protein excretion was remarkably reduced to 0.6 g/day without adversely affecting blood pressure. During the treatment period, proteinuria was maintained at less than 0.6 g/day and renal function remained normal. We propose that glomerular hypertension caused by insufficient suppression of the renin-angiotensin system was an essential factor underlying the increased urinary protein excretion in this patient. Combination therapy of an ARB and an ACE inhibitor appears to have a beneficial effect in patients with IgA nephropathy patients with persistent glomerular hypertension.     

Immunoglobulin A nephropathy complicating ulcerative colitis

Ulcerative colitis is rarely associated with immunoglobulin A nephropathy (IgAN). The development of IgA nephropathy complicates further the clinical course of patients with ulcerative colitis. A 72-year old man with a 30-year history of ulcerative colitis requiring colectomy and modest renal insufficiency secondary to complications of nephrolithiasis and renal artery stenosis developed glomerular hematuria, proteinuria and progressive renal failure. Percutaneous kidney biopsy revealed IgAN with extensive glomerular and interstitial sclerotic changes. After resection of a chronically infected ileo-rectal pouch, renal function improved, while hematuria and proteinuria gradually disappeared without specific treatment of the IgAN. The manifestations of IgAN complicating ulcerative colitis can be improved with effective treatment of the bowel disease even when there are extensive sclerotic changes in the kidneys.     

Proteinuria in hypertension

It had been previously thought that protein excretion in hypertensive nephrosclerosis was less than 0.5 to 1.0 g/24 h. Furthermore, it was believed that proteinuria in the nephrotic range associated with hypertension was probably due to primary renal disease, malignant hypertension, renal artery stenosis, or pheochromocytoma. We report eight patients with biopsy-proven hypertensive nephropathy and heavy proteinuria in the absence of malignant hypertension or renal artery stenosis. The 24-hour protein excretion ranged from 2.7 to 4.3 g. All patients had renal insufficiency, with serum creatinine ranging from 2.0 (176.8) to 7.8 mg/dL (689.5 mumol/L). Renal function worsened in most patients during the follow-up period despite adequate control of the hypertension, and three patients had to be started on hemodialysis. Three patients died during the follow-up period. We conclude that hypertensive nephrosclerosis must be included in the differential diagnosis of marked proteinuria in patients with essential hypertension and that heavy proteinuria, along with renal insufficiency, are poor prognostic indicators in such patients.     

Steroid therapy in IgA nephropathy: a retrospective study in heavy proteinuric cases

29 patients with IgA nephropathy whose proteinuria persisted at a level of 2.0 g/day or more and who received prednisolone treatment for 1-3 years were retrospectively evaluated on their clinical courses. 13 of 14 patients with renal dysfunction of less than 70 ml/min in initial creatinine clearance (Ccr) values subsequently entered a progressive course during a follow-up period of 47 months, leading to end-stage renal failure in 8 cases. On the other hand, only 1 of the other 15 patients with preserved renal function of 70 ml/min or more ended up with end-stage renal failure during a follow-up period of 74 months, although 7 underwent a progressive course. Three patients in the latter group experienced a prominent reduction in proteinuria to less than 1.0 g/day and maintained renal function. Meanwhile, the steroid group of moderate proteinuric patients with a creatinine clearance greater than 70 ml/min had a benign course, while the nonsteroid group had an unfavorable one. These results suggest that steroid therapy in IgA nephropathy may be able to stabilize a progressive course, especially in the early stage of the disease, although, because they come from an uncontrolled study, a definite conclusion cannot be drawn.     

A prospective study on the impact of the renal biopsy in clinical management

A three year prospective study involving 80 patients was conducted to assess the impact of renal biopsy on clinical management. Pre-biopsy predicted histologic diagnosis was changed in 35 (44%) of the patients as a result of the biopsy. Prognosis changed in 45 (57%) of the patients. Therapy changed in 25 (31%) of the patients. These results suggest that, overall, renal biopsy had a marked effect on management. However, we identified subgroups of patients who were unlikely to have their management changed as a result of the biopsy: of 16 patients with a pre-biopsy diagnosis of IgA nephropathy, 1 (6%) had treatment changed because of the biopsy; and of the 50 patients without heavy proteinuria (greater than 3 g/24 h), 10 (20%) had treatment changed because of the biopsy. Although our overall results suggest an important role for renal biopsy in clinical management, renal biopsy has the least apparent impact in patients with a pre-biopsy diagnosis of IgA nephropathy or without heavy proteinuria.     

强直性脊柱炎肾损害的临床病理特点

目的探讨强直性脊柱炎（AS）合并肾损害的临床及病理特点。方法回顾性分析18例经肾脏活体组织检查的AS患者的临床及肾脏病理表现。结果18例患者中,9例呈隐匿性肾小球肾炎表现,5例呈慢性肾小球肾炎表现,1例呈肾病综合征表现,3例为慢性肾功能不全;4例血压增高,14例血压正常。24h尿蛋白定量平均为（1．17±1．39）g。15例肾功能正常,3例肾功能异常患者血肌酐平均为（153．2±36．8）umol／L。8例患者血清IgA水平升高,10例c反应蛋白升高,13例红细胞沉降率（EsR）增快,且血清IgA水平和C反应蛋白呈正相关（r=0．707,P=0．001）,血清IgA水平和ESR呈正相关（r=0．858,P〈0．001）。病理检查结果发现15例为IgA肾病（其中10例为轻度系膜增生性肾炎,1例为轻度系膜增生性肾炎并慢性肾小管间质肾病,2例为局灶增生性肾炎,1例为局灶增生坏死性肾炎,1例为局灶节段性肾小球硬化症）,1例为膜性肾病,1例为局灶增生性肾炎伴慢性肾小管间质肾病,1例为慢性。肾小管间质肾病。有慢性肾小管间质肾病者均有服中药史。结论AS相关性肾损伤的病理改变多样,但主要为IgA肾病,也可表现为膜性肾病、局灶增生性肾炎和慢性肾小管间质。肾病,其肾损伤可能与AS疾病本身和（或）治疗用药相关。     

Prevention and treatment of diabetic nephropathy with blood pressure lowering drugs

Summary: Diabetic nephropathy is a clinical syndrome characterized by persistent albuminuria (>300 mg/24 h), a relentless decline in glomerular filtration rate (GFR), and raised arterial blood pressure. the prevalence of abnormal elevated albumin excretion rate (>30 mg/24 h) is approximately 40% in insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) patients. Diabetes has become the leading cause of end-stage renal failure in the United States of America and Japan and it remains the second leading cause in Europe. Patients suffering from diabetic nephropathy have an enormous increase in morbidity and mortality from cardiovascular disease in addition to renal death. Elevated blood pressure is an early and frequent phenomenon and furthermore accelerates the course of diabetic nephropathy. Studies in humans suggest that angiotensin-converting enzyme (ACE) inhibitors postpone and may even prevent progression to clinical overt diabetic nephropathy in normotensive IDDM and NIDDM patients with persistent microalbuminuria. Conventional antihypertensive therapy and ACE inhibition usually combined with a diuretic reduces albuminuria and postpones renal insufficiency in hypertensive IDDM patients with overt nephropathy. A more beneficial effect on the rate of decline in glomerular filtration rate has been demonstrated by ACE inhibitors compared to conventional antihypertensive treatment in IDDM patients with diabetic nephropathy and reduced kidney function (serum creatinine >133 mmol/L). These findings suggest that ACE inhibition causes renal protection (i.e. a beneficial effect on kidney function [structure] above and beyond what would be expected from blood pressure lowering effect alone). Finally, it should be stressed that ACE inhibition and conventional antihypertensive treatment postpone end-stage renal failure and improve survival in diabetic nephropathy.